This invention relates to production of glutamate using wild type Bacillus methanolicus.
Microorganisms that utilize one-carbon compounds more reduced than carbon dioxide (methylotrophs) are diverse and ubiquitous. Anthony, The Biochemistry of Methylotrophs, page 3 (Academic Press, London 1982); Hanson, Adv. Appl. Microbiol., 26:3 (1980). Those methylotrophic bacteria reported to utilize methane are all gram-negative and nearly all have an obligate requirement for one-carbon compounds as energy sources. Anthony, supra; Whittenburg et al. J. Gen. Microbiol., 61: 219-226 (1970). Bacteria that grow on methanol and methylamines but not methane include several facultative as well as obligate methylotrophs. Anthony, supra; Hanson, supra. All the obligate methylotrophs unable to utilize methane are gram-negative aerobic bacteria. Anthony, supra.; Whittenburg, supra. Of the facultative methylotrophs isolated that utilize methanol, methylamine or both, only a few were gram positive and were assigned to the genera Bacillus, Corynebacterium, Arthrobacter, or Nocardia. Akiba et al, J. Ferment. Technol., 48:323-328 (1970); Clement et al. Abstracts of the Fifth International Symposium Microbiol. Growth on C.sub.1 Compounds, p. 69 (Free Univ. Press, Amsterdam 1986); Hazen et al, Arch. Microbiol., 135:205-210 (1983); Mimura et al., J. Ferment. Technol., 5:243-252 (1978).
Some species of facultative gram positive methyltrophs that utilize methanol, methylamine or both have now been classified together and named Bacillus methanolicus. Arfman et al., Int. J. System. Bact., 42:438 (1992). Characteristics of Bacillus methanolicus are identified in Arfman et al., cited supra.
The industrial advantages of a thermophilic methanol utilizing fermentation process at elevated temperatures have been described, Snedecor and Cooney, Appl. Microbiol., 22:112-1117 (1974). For example, use of elevated temperatures can significantly reduce cooling costs. Use of methanol as a carbon and energy source is cost efficient because of its wide availability and low cost. A methanol utilizing, thermophilic mixed culture that included an endospore-forming species was selected by Snedecor and Cooney; however, Snedecor and Cooney, were unable to isolate a pure culture capable of growth on methanol. It is extremely difficult or impossible to isolate appropriate wild type strains from mixed or impure cultures.
Large scale production of glutamic acid is desired for many commercial applications. For example, glutamic acid is used in the production of moisturizers in cosmetics, gelatinizing agents in vegetable oils, for oil dispersion, and as a seasoner for foods. The demand for monosodium glutamate exceeds 300,000 tons per year. To date no production of amino acids, such as glutamic acid, using an isolated wild type Bacillus species capable of rapid growth on methanol at temperatures above 50.degree. C. has occurred.
Accordingly, there is a need for a method of producing glutamic acid using a wild type Bacillus methanolicus which exhibits sustained growth on methanol at a temperature of at 50.degree. C. There is also a need for an inexpensive method of producing glutamic acid on an industrial scale.